Calculation of RMS Values for Variable Frequency Sinusoidal Signals, Using Phasors and Digital SAL and CAL Filters

The accurate measurement of RMS values of voltage and current is crucial for the monitoring and protection of power systems and in general for electrical power distribution systems. The authors in this paper have developed an algorithm to calculate the RMS value of sinusoidal signals of varying frequency, by applying phasors obtained from digital filters SAL and CAL. In conditions in which the frequency of the grid varies, a phase shift is presented in the phasor of the grid voltage which is used for the design of a regulator that allows to obtain accurate RMS voltage values. The choice of the SAL and CAL digital filters is due to their low computational requirement, so they can be implemented in general-purpose microcontrollers.

Enhancing Magnetic Hyperthermia Nanoparticle Heating Efficiency with Non-Sinusoidal Alternating Magnetic Field Waveforms

For decades now, conventional sinusoidal signals have been exclusively used in magnetic hyperthermia as the only alternating magnetic field waveform to excite magnetic nanoparticles. However, there are no theoretical nor experimental reasons that prevent the use of different waveforms. The only justifiable motive behind using the sinusoidal signal is its availability and the facility to produce it. Following the development of a configurable alternating magnetic field generator, we aim to study the effect of various waveforms on the heat production effectiveness of magnetic nanoparticles, seeking to prove that signals with more significant slope values, such as the trapezoidal and almost-square signals, allow the nanoparticles to reach higher efficiency in heat generation. Furthermore, we seek to point out that the nanoparticle power dissipation is dependent on the waveform’s slope and not only the frequency, magnetic field intensity and the nanoparticle size. The experimental results showed a remarkably higher heat production performance of the nanoparticles when exposed to trapezoidal and almost-square signals than conventional sinusoidal signals. We conclude that the nanoparticles respond better to the trapezoidal and almost-square signals. On the other hand, the experimental results were used to calculate the normalized power dissipation value and prove its dependency on the slope. However, adjustments are necessary to the coil before proceeding with in vitro and in vivo studies to handle the magnetic fields required.

An Eight-Channel Switching-Linear Hybrid Dynamic Regulator with Dual-Supply LDOs for Thermo-Optical Tuning

<div>A novel switching-linear hybrid dynamic regulator with dual-supply LDOs for thermo-optical tuning is presented in this brief. Compared with conventional designs, the proposed design leverages the intrinsic dual supplies to extend the operating range of the LDOs, and increases the thermo-optical tuning efficiency by reducing the dropout of the LDOs through dynamic voltage tracking. It can simultaneously regulate eight output channels and track 0.8 V_pp sinusoidal waveforms at different frequencies. Significant efficiency improvement of the proposed design is achieved for envelope signals with a small difference, which is common in thermo-optical tuning. Implemented in 130 nm CMOS process, the proposed design has a total chip area of 0.675 mm². The proposed design achieves a conversion efficiency of 88% at 1 V output driving a 200 ohms load. Its dynamic efficiency is about 80% when tracking 50 kHz sinusoidal signals.</div>

An Eight-Channel Switching-Linear Hybrid Dynamic Regulator with Dual-Supply LDOs for Thermo-Optical Tuning

<div>A novel switching-linear hybrid dynamic regulator with dual-supply LDOs for thermo-optical tuning is presented in this brief. Compared with conventional designs, the proposed design leverages the intrinsic dual supplies to extend the operating range of the LDOs, and increases the thermo-optical tuning efficiency by reducing the dropout of the LDOs through dynamic voltage tracking. It can simultaneously regulate eight output channels and track 0.8 V_pp sinusoidal waveforms at different frequencies. Significant efficiency improvement of the proposed design is achieved for envelope signals with a small difference, which is common in thermo-optical tuning. Implemented in 130 nm CMOS process, the proposed design has a total chip area of 0.675 mm². The proposed design achieves a conversion efficiency of 88% at 1 V output driving a 200 ohms load. Its dynamic efficiency is about 80% when tracking 50 kHz sinusoidal signals.</div>

Measurement of the Parameters of Multiple Sinusoids Based on Binary Data

<p>This paper introduces a novel procedure for quick estimation of the parameters of a sum of sinusoidal signals based on one-bit measurements. Amplitude, phases and, frequencies of the signal components are assumed unknown, as well as the threshold level of the comparator used to produce measurement results. To provide enough information at the one-bit quantizer input, a sinewave is assumed to dither one of the two comparator's inputs. To ease the procedure's application, only the peak-to-peak amplitude of this dither signal is assumed known. Theoretical, simulation-based and experimental results validate the presented approach.</p>

Measurement of the Parameters of Multiple Sinusoids Based on Binary Data

<p>This paper introduces a novel procedure for quick estimation of the parameters of a sum of sinusoidal signals based on one-bit measurements. Amplitude, phases and, frequencies of the signal components are assumed unknown, as well as the threshold level of the comparator used to produce measurement results. To provide enough information at the one-bit quantizer input, a sinewave is assumed to dither one of the two comparator's inputs. To ease the procedure's application, only the peak-to-peak amplitude of this dither signal is assumed known. Theoretical, simulation-based and experimental results validate the presented approach.</p>